TREATMENT OF NEUROGENIC CLUBFOOT

Abstract

The neurogenic clubfoot is composed of several deformities – such as cavus and equinus, hind foot varus, supination and adduction of the forefoot – which develop due to the neurological disease leading to muscle imbalance. Whereas over-activity and spasticity occur after damage of the central nervous system, flaccid paralysis is the result of damage of the spinal motor neuron or the nerve itself. Local overload at the lateral border of the foot, poor stability and small supporting area may interfere with function and hence require treatment of the deformity. The primary aim is a functioning foot. Treatment options are conservative means or surgical procedures.

Insoles are applied to correct the foot position: a lateral support forces the foot into valgus and pronation being effective only when loaded and worn in reinforced shoes. They can also be used to distribute pressure in case of local overload and sores. An individually manufactured foot orthosis provides more stability. If the forces are still overly big, the lever arm of an ankle foot orthosis is required.

Surgical procedures may be carried out in addition to or instead of conservative means. Skeletal surgery should not be performed early because the neurological disease persists despite the local correction and increases the risk for recurrences. Stiffening of the foot needs to be avoided in order to preserve function. Stiffness due to cavus is reduced by a Steindler release of the plantar fascia. Equinus should not be overstressed. If necessary, it is corrected by heel cord lengthening resulting in a persistent loss of force, or by aponeurotomy maintaining force but being less efficient to gain length. To balance supination, split or complete transfer corrects the pull of hyperactive anterior or posterior tibial muscles. Lacking skeletal deformation is a prerequisite for these soft tissue procedures. Thus their presence requires bony correction alone or in addition to soft tissue surgery. The varus of the os calcis is best corrected by an original or modified Dwyer valgus osteotomy. Cavus, supination and adduction deformity can all be corrected at the midfoot. These procedures preserve mobility and hence function of the foot. Severely contracted feet, however, may need corrective fusions. Nevertheless, stiffness is badly tolerated. An alternative is application of an external fixater of the Ilizarov type to correct the skeletal deformity and followed by an additional corrective osteotomy.

Botulinum toxin A paralysing a muscle for three months can be used to switch off overactive anterior or posterior tibial muscles in order to delay surgery or to prevent pull out after transfer. Application of casts to stretch overly short muscles can help to keep the deformity under control, but they need to be followed by splints in order to avoid early recurrence.